The automotive industry has utilized an electric starter engine powered by an automotive vehicle's 12-volt battery for an operator to start the internal combustion engine of the vehicle. However, known automotive designs include using an engine controller to temporarily shut off the engine to reduce fuel consumption and emissions if the engine is in an idle-engine state. An example of an idle-engine state includes the vehicle being stopped for a predetermined time threshold such as can occur when the vehicle encounters a traffic light. These designs usually employ an integrated starter/generator either on the front end accessory drive or engaged with the flywheel in a suitable arrangement. This typically requires using a nominal 42-volt electrical system instead of a nominal 12-volt electrical system for all but smaller displacement engines. Such designs add considerable complexity to the vehicle and add corresponding cost and weight. After an idle engine shut-off has occurred, the engine controller uses the electric starter motor to restart the engine when a predetermined engine-start condition exists. An example of an engine-start condition includes the presence of the key in the ignition (“Key-On”) since the idle engine shut-off and the absence of brake pressure.
Known designs of certain diesel trucks (such as that disclosed in U.S. Pat. No. 5,528,901) include using an electric starter motor to start an auxiliary diesel engine to power an air compressor to power a separate pneumatic starter motor of a main diesel engine to start the main diesel engine. The operator uses only the auxiliary diesel engine when the truck is at a truck stop to power auxiliary equipment, and the operator starts and uses the main diesel engine when the truck is traveling on the road.
Still, scientists and engineers continue to seek improved automotive starting systems.